Heat Resistant Toughened Themoplastic Composition for Injection Molding

Abstract

Injection molded parts with a small dimension that exhibit high heat resistance are described. Thermoplastic compositions that can be utilized to form the injection molded parts are described. The thermoplastic composition includes a polyarylene sulfide and a crosslinked impact modifier. The thermoplastic composition can also include siloxane polymers, thermoplastic elastomers, or other additives that can further improve the characteristics of the injection molded parts.

What is claimed is: 
     
         1 . An injection molded part having a thickness of about 100 millimeters or less, the injection molded part being formed from a thermoplastic composition that includes a polyarylene sulfide and a crosslinked impact modifier, the injection molded part exhibiting a notched Charpy impact strength of about 3 kJ/m 2  or greater as measured according to ISO Test No. 179-1 at a temperature of 23° C., the injection molded part exhibiting about 60% or more strength retention following heat aging at 165° C. for 1000 hours. 
     
     
         2 . The injection molded part of  claim 1 , wherein the injection molded part is a fastener. 
     
     
         3 . The injection molded part of  claim 2 , wherein the fastener is a cable tie, a clip, a band, a harness, a tape, a clamp, or a cable tie saddle. 
     
     
         4 . The injection molded part of  claim 1 , the injection molded part exhibiting a notched Charpy impact strength of about 8 kJ/m 2  or greater as measured according to ISO Test No. 179-1 at a temperature of −30° C. 
     
     
         5 . The injection molded part of  claim 1 , wherein the injection molded part meets the V-0 flammability standard at a thickness of 0.2 millimeters. 
     
     
         6 . The injection molded part of  claim 1 , wherein the injection molded part exhibits a flexural modulus of about 2500 MPa or less as determined according to ISO Test No. 178. 
     
     
         7 . The injection molded part of  claim 1 , wherein the polyarylene sulfide is a polyphenylene sulfide. 
     
     
         8 . The injection molded part of  claim 1 , wherein the impact modifier is an olefinic terpolymer. 
     
     
         9 . The injection molded part of  claim 1 , wherein the crosslinked impact modifier comprises the reaction product of an epoxy functionality of the impact modifier and a crosslinking agent or the reaction product of maleic anhydride functionality of the impact modifier and a crosslinked agent. 
     
     
         10 . The injection molded part of  claim 9 , wherein the crosslinking agent is terephthalic acid. 
     
     
         11 . The injection molded part of  claim 1 , the thermoplastic composition further comprising a siloxane polymer. 
     
     
         12 . The injection molded part of  claim 11 , wherein the siloxane polymer is a polydimethylsiloxane. 
     
     
         13 . The injection molded part of  claim 12 , wherein the polydimethylsiloxane is ultrahigh molecular weight polydimethylsiloxane. 
     
     
         14 . The injection molded part of  claim 11 , the thermoplastic composition further comprising fumed silica. 
     
     
         15 . The injection molded part of  claim 11 , the thermoplastic composition further comprising a coupling agent. 
     
     
         16 . The injection molded part of  claim 15 , wherein the coupling agent is an amino silane coupling agent. 
     
     
         17 . The injection molded part of  claim 1 , the thermoplastic composition further comprising a thermoplastic elastomer. 
     
     
         18 . The injection molded part of  claim 17 , wherein the thermoplastic elastomer has a repeating structure represented by (A-B) n , wherein A is a hard segment and B is a soft segment. 
     
     
         19 . The injection molded part of  claim 18 , wherein the thermoplastic elastomer comprises alternating blocks of polyamide and polyether. 
     
     
         20 . The injection molded part of  claim 1 , the thermoplastic composition further comprising one or more additives. 
     
     
         21 . The injection molded part of  claim 20 , wherein the one or more additives comprises one or more fillers. 
     
     
         22 . The injection molded part of  claim 21 , wherein the one or more fillers comprises fibrous fillers. 
     
     
         23 . A method for forming the injection molded part of  claim 1 , the method comprising:
 injecting the thermoplastic composition into a mold cavity, the thermoplastic composition having a melt viscosity of about 3 kilopoise or less as determined by a capillary rheometer at a temperature of 310° C. and a shear rate of 1200 seconds −1 ; and   ejecting the molded part from the mold cavity.